Understanding Viral Structures: Helical, Icosahedral & Complex

The three basic structures of viruses are:

1. Helical: In this structure, the capsid proteins are arranged in a helical pattern around the RNA genome. Examples of helical viruses include tobacco mosaic virus and influenza virus.

2. Icosahedral: In this structure, the capsid proteins are arranged in a symmetrical, 20-sided shape around the RNA or DNA genome. Examples of icosahedral viruses include herpes simplex virus and adenovirus.

3. Complex: In this structure, the capsid proteins are arranged in a more complex pattern that does not fit into either the helical or icosahedral categories. Examples of complex viruses include poxvirus and bacteriophage.